The present invention relates to a ski, and more particularly to a ski that can be used for both uphill and downhill skiing.
Skiing is a favorite winter sport and one of the oldest forms of transportation on snow covered grounds. Snow skis are attached to a skier""s boots and are used either for skiing downhill or for cross-country and uphill skiing. Cross-country and uphill skis are relatively long, slender, have a uniform width, a light weight and are thicker in the middle compared to the front and back ends. Downhill skis are shorter, wider, have an hour-glass shape, uniform thickness and a heavier weight. For downhill skiing the bottom surface of the ski that comes in contact with the snow covered ground needs to be smooth, whereas for cross-country and uphill skiing the bottom surface is rough or has ridges in order to provide traction. In some cases a special type of wax is applied to the bottom surface of a cross-country and uphill ski in order to make it stick to the snow covered grounds.
A special type of skiing is called xe2x80x9cTelemark skiingxe2x80x9d, named after a region in Norway. Telemark skiing was developed by Sondre Norheim and it involves uphill walking and downhill skiing. Telemark skiing may also include telemark turns (where the outside ski is advanced considerably ahead of the other ski and then turned inward at a steadily widening angle until the turn is completed), skating sections and jumps. In order to accommodate both the uphill walking and the downhill skiing, the texture of the bottom surface of the ski needs to be adapted.
One way of changing the texture of the bottom ski surface from smooth to rough is to attach climbing skins. There are two types of climbing skins, woven fabrics and plastic skins. Woven fabrics are usually attached to the bottom surface of a ski via an epoxy. In some cases, woven fabrics may have one self-sticking surface covered with wax paper. The wax paper is removed and the self-sticking surface of the woven fabric is attached to the bottom surface of the ski. The wax paper needs to be reapplied on the self-sticking surface of the woven fabric after the woven fabric is removed from the bottom surface of the ski. This process of removing and reattaching the wax paper on the self-sticking surface of the woven fabric is very cumbersome and especially difficult under harsh weather condition such as wind, snow or rain. Plastic skins are usually attached to the bottom surface of a ski via mechanical means. However, keeping the climbing skins attached to the bottom surface of a ski poses a significant challenge. The epoxy needs to be reapplied several times on the woven fabrics and the mechanical attachment of the plastic skins may break or needs to be reattached. Furthermore, the skier needs to carry with him the climbing skins during the downhill skiing and accessories for applying and carrying the climbing skins during both the uphill and the downhill skiing, which adds weight to the skier. Some systems are bulky to transport, do not function properly when they get wet and need to be frequently dried. It usually takes a long time to mount and dismount both types of the climbing skins on the skis and especially difficult under harsh weather condition such as wind, snow or rain.
Another method of providing traction during uphill and cross-country skiing is to use waxes. The wax melts and makes the bottom ski surface stick to the snow covered ground. However, waxes usually have a limited operational temperature range and do not provide sufficient traction.
There is a need for a ski that can accommodate both uphill and downhill skiing without the disadvantages of the existing systems.
In general, in one aspect, the invention features a ski including an elongated body having a bottom surface and a surface modifier. The surface modifier has a first surface with a smooth texture and a second surface opposite to the first surface with a rough texture. The surface modifier is reversibly attached to the bottom surface of the elongated body thus providing the bottom surface with a smooth texture suitable for downhill skiing when the second surface is attached to the bottom surface and with a rough texture suitable for uphill and cross country skiing when the first surface is attached to the bottom surface.
Implementations of this aspect of the invention may include one or more of the following features. The surface modifier may cover either the entire bottom surface of the elongated body or part of the bottom surface of the elongated body. In particular, the surface modifier may cover a centrally arranged and axially extending portion of the bottom surface of the elongated body. The elongated body further includes a front portion, a middle portion and a back portion and the surface modifier may have a first segment attached to the bottom surface of the front portion and a second segment attached to the bottom surface of the back portion. The surface modifier may be attached to the bottom surface via a tongue and groove type of attachment. In order to accomplish this type of attachment, the surface modifier may include at least one edge forming the male member of the tongue and groove attachment and the bottom surface of the elongated body may include at least one groove forming the female member of the tongue and groove attachment. Alternatively, the surface modifier may include at least one groove forming the female member of the tongue and groove attachment and the bottom surface of the elongated body includes at least one edge forming the male member of the tongue and groove attachment. The surface modifier may also be attached to the bottom surface via a dove tail type of attachment. The surface modifier may also be attached to the bottom surface by at least one screw and/or at least one bracket. The elongated body and the surface modifier may be made of a material such as wood, metal, plastic, foam, composites, laminates, and combinations thereof. The rough textured surface of the surface modifier may include at least one downward extending protrusion or at least one groove having a height in the range of 3 millimeters to 0.1 millimeters. The ski may further include a binding arranged on the top surface of the middle portion of the elongated body for attaching a skier""s boot.
In general, in another aspect, the invention features a ski system including a set of two skis each ski having an elongated body having a bottom surface and a surface modifier. The surface modifier has a first surface with a smooth texture and a second surface opposite to said first surface with a rough texture. The surface modifier is reversibly attached to the bottom surface of the elongated body thus providing the bottom surface with a smooth texture suitable for downhill skiing when the second surface is attached to the bottom surface and with a rough texture suitable for uphill and cross country skiing when the first surface is attached to the bottom surface.
In general, in another aspect, the invention features a method of skiing using a ski system including a set of two skis each ski having an elongated body having a bottom surface and a surface modifier. The surface modifier has a first surface with a smooth texture and a second surface opposite to said first surface with a rough texture, a method of skiing. The method of skiing includes the steps of attaching the first smooth textured surface of the surface modifier to the bottom surface of each ski thus providing the bottom surface with a rough texture and then skiing uphill. Next, reversing the surface modifier and attaching the second rough textured surface of the surface modifier to the bottom surface of each ski thus providing the bottom surface with a smooth texture and then skiing downhill.
Among the advantages of this invention may be one or more of the following. The invention allows a skier to ski uphill and downhill without having to carry climbing skins or any other additional equipment for converting the uphill skis into downhill skis. The invention provides a ski that is easy to use. Since it does not use climbing skins it does not require the maintenance that is associated with them, such as needing to be dried, epoxied to the bottom of a ski or attaching wax paper to its self-sticking surface for storage. The ski according to this invention has a performance during down hill skiing comparable to a good Telemark ski. The performance of this ski during uphill skiing is at least as good or even better than a good wax-less cross-country ski. The time that it takes to convert the ski from the uphill to the downhill configuration is of the order of seconds. This ski can be used under any kind of weather conditions such as wind, snow or rain and with both hard-packed and light-packed type of snow. This ski may be used for uphill, downhill, cross-country, Telemark and Randonnee type of skiing, among others.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and description below. Other features, objects and advantages of the invention will be apparent from the following description of the preferred embodiments, the drawings and from the claims.